Depicted in FIG. 1 is a cutaway view of a kinetic energy (KE) projectile 10 of the prior art as part of a cartridge 12 chambered in a gun tube 14. As well known in the art, projectile 10 is comprised of a sabot 16, a projectile nose 18, a solid projectile base rod 20 and a rear fin section 22. Nose 18 is attached to rod 20 by threads (not shown) and fin section 22 is attached to rod 20 by threads (not shown). Sabot 16 is attached to rod 20 by threads or buttress grooves (not shown). Projectile 10 is referred to as an in-bore KE projectile due to the fact that it has sabot 16 attached to projectile rod 16.
Cartridge 12 consists of projectile 10 which is attached to an obturator 24, which obturator 24 is in turn attached to a cartridge case 26. Cartridge case 26 contains a primer 28 and a propellant 30. Primer 28 is used to ignite propellant 30 in cartridge case 26. Following ignition of propellant 30, in-bore projectile 10 travels up gun tube 10 and then exits gun tube 10. This propellant/projectile/gun tube interface is what determines the velocity of the in-flight projectile.
In-flight, projectile 10 does not have sabot 16 attached. Instead, in-flight projectile 10 is comprised of nose 18, rod 20 and fin section 22. The function of sabot 16 is to fill gun tube 14 during launch and to carry projectile 10. Once in-bore projectile 10 exits gun tube 14, sabot 16 is discarded and in-flight projectile 10 continues on to the target—which is typically heavy armor. Upon impact with the target, rod 20, usually made of tungsten or depleted uranium (DU), defeats the target by penetrating it and passing through it.
It is the kinetic energy of projectile 10, the shape of projectile 10, and the angle of impact and material of rod 20 that determine the thickness of armor that rod 20 penetrates. Various attempts have been made to change one or more of these factors to increase the thickness of armor that can be defeated.
For example, one known way to increase the penetration capability of rod 20 is to increase the length of rod 20. However, since rod 20 in cartridge 12 usually is at a maximum length to fit within cartridge 12 already and/or for cartridge 12 to fit in the gun, increasing the length of rod 20 in cartridge 12 is not an option.